Boat raising and lowering gear



Feb; 8, 1927. 6 C. D. M LACHLAN BOAT RAISING AND LOWERING GEAR Filed Dec, 25: 1925 FIG! &

Patented Feb. 8, 1927.

FEQE.

BOAT RAISING AND LOWERING GEAR.

Application filed December 23, 1925, Serial No. 77,325, and in Great Britain August 25, 1825.

This invention relates to boat raising and lowering gear of the type in which the davits are mounted on and move over paral lel tracks extended down the ships side and provided with stops for arresting the davits at the end of a predetermined travel, the boat, on arrest of the davits, being free to move separately from the davits under the control of the winch and the falls. 7

In gear of this type the load on the winch motor varies according to the position of the davits, the load being greater when the davitsand therewith the boats are being moved along the tracks than when the 5 davits are at rest on the stops and the boat alone is being raised or lowered.

The invention, which has for its object to vary the purchase of the winch drums to correspond with the variations in the load thereon, consists in the incorporation in a boat raising and lowering gear of this type of a winch of which the drum or each drum is stepped to form two grooved fallreceiving cylindrical sections of different diameters joined by a grooved conical 'section, the gear being so arranged that the section of greater diameter is operative when the boat alone is being raised or lowered and that the section of less diameter is operative when the davits and the boat are being raised or lowered concomitantly.

'The invention is illustrated in the accompanying drawing in which Fig. 1 is a diagram of a boat raising and lowering gear of which the winch is equipped with two stepped drums, certain parts of the front davit and the front track being broken away to expose the rear davit and the rear track, and Fig. 2 a detail view of a stepped winch drum drawn to a larger s'ale,

The boat raising and lowering gear shown comprises davits 1 mounted on and movable over parallel tracks 2 extended down the ships side and fitted with stops 3 which limit the downward travel of the davits 1. 4

To vary the purchase of the winch drums to correspond with the variations in the load thereon there is incorporated in the boat raising and lowering gear a winch l. provided with two drums 5, 6 each stepped to form two grooved fall-receiving cylindrical sections 7, 8 of different diameters joined by a grooved conical section 9. The length of the falls 10, 11 connecting'the boat 12 with the drums 5, 6 and the points of anchorage of the falls 10, 11 to the drums are such that the sections 8 are operative when the boat alone is being raised or lowered and that the sections 7 are operative when the davits and the boat are being raised or lowered concomitantly.

I claim:

The combination with a boat raising and lowering gearof the type described of a V winch having two drums each stepped to form two grooved fall-receiving cylindrical sections of different diameters joined by a grooved conical section, the section of greater diameter being operative when the boat alone is being raised or lowered and the section of lesser diameter being operative when the davits and the boat are being raised or lowered concomitantly, and gears connecting said drums.

In testimony whereof I have signed my name to this specification.

' C. I). MGLACHLAN. 

